目前我正在尝试重构一个多维数组，它是数据库查询的结果。目标是最终将数组编码为 JSON，如下所示，但是我编写的 php 函数不起作用（请参见最后的代码）：
desiredJSONoutput = {"TypeA":[
{"1":[
{"TypeB":[4,5]},
{"TypeC":[7,8,4]}]},
{"2":[
{"TypeB":[2,3]},
{"TypeC":[6]}]},
{"4":[
{"TypeB":[33,12]},
{"TypeC":[908]}]}]}
数据库结构为：
fromType fromID toType toID
-----------------------------------------------------
TypeA 1 TypeB 4
TypeA 1 TypeB 5
TypeA 1 TypeC 7
TypeA 1 TypeC 8
TypeA 1 TypeC 4
TypeA 2 TypeB 2
TypeA 2 TypeB 3
TypeA 2 TypeC 6
TypeA 2 TypeB 33
TypeA 2 TypeB 12
TypeA 2 TypeC 908
我当前的 sql 查询的结果是这个 php 数组：
Array
(
Array
(
['fromType'] => 'TypeA'
['fromID'] => '1'
['toType'] => 'TypeB'
['toID'] => '4'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '1'
['toType'] => 'TypeB'
['toID'] => '5'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '1'
['toType'] => 'TypeC'
['toID'] => '7'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '1'
['toType'] => 'TypeC'
['toID'] => '8'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '1'
['toType'] => 'TypeC'
['toID'] => '4'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '2'
['toType'] => 'TypeB'
['toID'] => '2'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '2'
['toType'] => 'TypeB'
['toID'] => '3'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '2'
['toType'] => 'TypeC'
['toID'] => '6'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '3'
['toType'] => 'TypeB'
['toID'] => '33'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '3'
['toType'] => 'TypeB'
['toID'] => '12'
)
Array
(
['fromType'] => 'TypeA'
['fromID'] => '3'
['toType'] => 'TypeC'
['toID'] => '908'
)
)
我认为在编码为 JSON 之前我需要的重组数组是：
Array
(
['TypeA'] => Array
(
['1'] => Array
(
['TypeB'] => Array
(
[0] => 4
[1] => 5
)
['TypeC'] => Array
(
[0] => 7
[1] => 8
[2] => 4
)
)
['2'] => Array
(
['TypeB'] => Array
(
[0] => 2
[1] => 3
)
['TypeC'] => Array
(
[0] => 6
)
)
['3'] => Array
(
['TypeB'] => Array
(
[0] => 33
[1] => 12
)
['TypeC'] => Array
(
[0] => 908
)
)
)
)
我不确定为什么下面的 PHP 代码没有将返回的 php 数组重构为我想要的结构：
class Utilities {
public function linksReEncode($rowsArray) {
$result = array();
foreach ($rowsArray as $row) {
$fromtype = $row['fromtype'];
$fromID = $row['fromID'];
$toType = $row['toType'];
$toID = $row['toID'];
$arr = $result[$fromType][$fromID][$toType];
array_push($arr, $toID);
}
}
}
根据进一步的研究和@Waygood 的第一个答案进行编辑，这是我现在正在使用并且正在工作的功能。我想知道是否有必要对现有密钥进行所有检查，这是否是实现这一目标的最经济的方法
public function linksReEncode($rows) {
$result = array();
foreach ($rows as $row) {
$fromType = $row['fromType'];
$fromID = $row['fromID'];
$toType = $row['toType'];
$toID = $row['toID'];
if(!array_key_exists($fromType, $result))
$result[$fromType] = array();
if(!array_key_exists($fromID, $result[$fromType]))
$result[$fromType][$fromID] = array();
if(!array_key_exists($toType, $result[$fromType][$fromID]))
$result[$fromType][$fromID][$toType] = array();
array_push($result[$fromType][$fromID][$toType], $toID);
}
return $result;
}